Maps for Open-Circuit Voltage Losses Caused by Defects in Metal Halide Perovskite Quantum Dot Solar Cells

Metal halide perovskite quantum dots (MHPQDs) have been promising candidates for next-generation solar cells in recent years due to their excellent photovoltaic properties. However, the microscopic dynamic processes leading to open-circuit-voltage losses induced by various defects are still ambiguous. Here, we present maps for the dependence of the voltage losses on the basic properties of defects based on Shockley–Read–Hall statistics combined with the Huang–Rhys multiphonon recombination model in MHPQD solar cells. We find that only deep-level defects with appropriate localization strength can lead to significant open-circuit voltage losses, which confirms the crucial role of the localization strength of defects in charge-carrier trapping, providing a potential explanation for some experimental observations. Moreover, we propose that defect pairs formed by two shallow-level defects could induce substantial open-circuit-voltage losses, even accounting for a small proportion of the total defect concentration. This may open up rapid potential channels for nonradiative recombination of charge-carriers. In addition, the influence of quantum dot radius and temperature on charge-carrier trapping by defects and the resulting voltage losses is also discussed. These results not only offer valuable insights into analyzing the underlying mechanisms of the voltage losses by defects in solar cells but also enrich the knowledge of the dynamic processes of charge-carrier trapping by defects in semiconductor devices.